US 12,105,378 B2
Light diffusion sheet, backlight unit, liquid crystal display device, information apparatus, and method for manufacturing light diffusion sheet
Satoshi Shiba, Tokyo (JP)
Assigned to KEIWA INCORPORATED, Tokyo (JP)
Filed by KEIWA Incorporated, Tokyo (JP)
Filed on Jan. 5, 2024, as Appl. No. 18/405,444.
Application 18/405,444 is a continuation of application No. PCT/JP2022/020856, filed on May 19, 2022.
Claims priority of application No. 2021-112634 (JP), filed on Jul. 7, 2021.
Prior Publication US 2024/0134228 A1, Apr. 25, 2024
Prior Publication US 2024/0231149 A9, Jul. 11, 2024
Int. Cl. G02F 1/00 (2006.01); G02F 1/1335 (2006.01); G02F 1/13357 (2006.01)
CPC G02F 1/133607 (2021.01) [G02F 1/133603 (2013.01); G02F 1/133611 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A backlight unit comprising a plurality of point light sources and a light diffusion sheet, wherein
the light diffusion sheet has: a first surface to be one of a light emission surface or a light incident surface; and a second surface that is located on an opposite side of the first surface and is to be an other of the light emission surface or the light incident surface,
the plurality of point light sources is disposed to face the light incident surface,
at least the first surface of the light diffusion sheet includes a light diffuser provided with a plurality of recesses arrayed in a two-dimensional matrix, and a plurality of luminance enhancers that is flatter than the light diffuser, and
the plurality of luminance enhancers is provided in a gradation pattern such that an arrangement density is higher in a region where a luminance is lower in a luminance distribution generated by the plurality of point light sources when the plurality of recesses is formed all over the first surface.